.tip
  position absolute
  color #fff
  background-color rgba(0,0,0,.75)
  padding 4px 6px
  opacity 0
  transition-property opacity 
  transition-duration .2s
  border-radius 2px
  font-size 12px
  &::before
    content ''
    left -5px
    top 50%
    position absolute
    width 0
    height 0
    line-height 0
    border 5px dashed rgba(0,0,0,.75)
    margin-top -5px
    border-right-style solid
    border-left none
    border-top-color transparent
    border-bottom-color transparent
	  border-right-color rgba(0,0,0,.75) 
